United States Drug Patent 5,211,954: Claim Scope, Expiration, Orange Book Status, and Temazepam Patent Landscape

U.S. Patent No. 5,211,954 protects a narrowly defined temazepam capsule formulation, not temazepam as a molecule. The claims require a hard gelatin capsule containing crystalline temazepam with a specific dose, surface area, and particle-size distribution. The patent issued on May 18, 1993, and its ordinary 17-year patent term would have ended on May 18, 2010, absent a terminal disclaimer or patent-term adjustment. The claims therefore do not create a current U.S. patent barrier to generic temazepam capsules. [1]

What does U.S. Patent 5,211,954 claim?

The patent claims a hard gelatin capsule containing crystalline temazepam in a particular physical form and dose range.

Claim element	Claim 1	Claim 2
Dosage form	Hard gelatin capsule	Hard gelatin capsule
Active ingredient	Crystalline temazepam	Crystalline temazepam
Temazepam amount	6 to 8 mg	7.5 mg
Specific surface area	0.65 to 1.1 m²/g	0.65 to 1.1 m²/g
Particle-size limitation	95% below 65 microns	95% below 65 microns
Other formulation component	Pharmaceutically acceptable carrier	Pharmaceutically acceptable carrier
Transitional language	"Consisting essentially of"	"Consisting essentially of"

The claims are formulation claims. They do not cover:

Temazepam generally;
Every temazepam capsule;
Temazepam tablets or liquids;
A 15 mg, 22.5 mg, or 30 mg capsule unless the formulation otherwise falls within the claimed dose range;
Temazepam having a different surface area;
Temazepam with 5% or more of the particles at or above 65 microns;
A capsule lacking the specified crystalline material.

Claim 2 is a narrower species claim directed to the 7.5 mg strength. Claim 1 covers the broader 6-to-8 mg range and therefore encompasses a 7.5 mg formulation when every other limitation is satisfied.

How should the claim language be interpreted?

What does "consisting essentially of" mean?

"Consisting essentially of" is an intermediate transitional phrase. It generally permits additional ingredients that do not materially affect the basic and novel characteristics of the claimed formulation. The language is narrower than "comprising" but broader than "consisting of." [2]

For this patent, the basic and novel characteristics are likely tied to the physical properties of the crystalline temazepam and the resulting capsule formulation. An accused formulation containing conventional excipients would not necessarily fall outside the claims. A formulation containing an additional ingredient that materially changes particle-size behavior, dissolution, crystallinity, or the relevant surface-area characteristics could present a stronger non-infringement position.

The phrase does not eliminate the requirement that the capsule contain a pharmaceutically acceptable carrier. A capsule containing only temazepam would not satisfy that express limitation unless the capsule or another component qualifies as the claimed carrier under the patent's construction.

What does the surface-area limitation require?

The active ingredient must have a specific surface area from 0.65 to 1.1 square meters per gram. This is a numerical limitation, not a general reference to micronized temazepam.

Surface area may vary depending on:

Measurement technique;
Gas adsorption method;
Sample preparation;
Drying conditions;
Particle agglomeration;
Crystal habit;
Batch handling.

The patent's specification and prosecution history would control the applicable measurement methodology. A generic manufacturer could challenge infringement by showing that its crystalline temazepam falls outside the range under the legally applicable test, even if its nominal particle size is similar.

What does "95% ... less than 65 microns" require?

The claim requires that at least 95% of the temazepam particles have a size below 65 microns. The limitation is a distribution requirement rather than a requirement that every particle be below 65 microns.

Potential measurement issues include:

Whether the percentage is measured by particle count, volume, or mass;
Whether agglomerates are treated as individual particles;
Whether the test measures primary particles or secondary agglomerates;
Whether the 65-micron boundary is exclusive;
Whether the claim's intended method appears in the patent specification.

A product with 95% exactly below 65 microns presents a boundary issue. A product with 94% below 65 microns would fall outside the literal wording, subject to any doctrine-of-equivalents analysis.

Does claim 2 cover all 7.5 mg temazepam capsules?

No. A 7.5 mg capsule must satisfy every additional limitation:

The temazepam must be crystalline.
Its specific surface area must be 0.65 to 1.1 m²/g.
At least 95% of the particles must be below 65 microns.
The active must be in a hard gelatin capsule.
The formulation must contain a pharmaceutically acceptable carrier.
The formulation must remain within the "consisting essentially of" boundary.

A 7.5 mg capsule using a different particle-size distribution, a different surface area, a noncrystalline form, a softgel shell, or a different delivery system would not literally satisfy claim 2.

What is the patent's likely priority and expiration timeline?

Event	Date or status
U.S. Patent No. 5,211,954 issued	May 18, 1993
Ordinary pre-Uruguay Round patent term	17 years from issue
Ordinary expiration date	May 18, 2010
Current enforceability	Expired under ordinary term
Current generic-entry effect	No operative exclusion based on this patent

Patents issued from applications filed before June 8, 1995 generally received a 17-year term from grant rather than the later 20-year term measured from the earliest effective nonprovisional filing date. The Uruguay Round Agreements Act changed the governing term for later-filed applications. [3]

The USPTO patent record should be used for any terminal disclaimer, reexamination certificate, correction, or term adjustment affecting the exact legal expiration date. The ordinary term, however, places the patent's expiration in 2010, well before current generic competition.

What is the Orange Book status of U.S. Patent 5,211,954?

U.S. Patent 5,211,954 does not create a current Orange Book obstacle for temazepam products because it has expired. FDA Orange Book listings identify patents submitted by NDA holders for approved drug products, but an expired patent cannot lawfully block an ANDA applicant from marketing a product after the patent term ends. [4]

Temazepam capsules are approved as immediate-release oral dosage forms, including the 7.5 mg strength associated with Restoril and generic products. The Orange Book's therapeutic-equivalence framework concerns approved products and regulatory substitutability. It does not independently extend an expired patent. [4]

Are Paragraph IV challenges relevant today?

A Paragraph IV certification is relevant when an ANDA applicant asserts that a listed patent is invalid, unenforceable, or will not be infringed. [5] For Patent 5,211,954, a current Paragraph IV challenge would have little practical value because the patent has already expired.

Before expiration, a generic applicant seeking approval before the patent's expiration could have:

Filed a Paragraph IV certification;
Triggered potential Hatch-Waxman litigation;
Obtained a 30-month stay if the statutory conditions were met;
Pursued a settlement permitting launch on a negotiated date.

After expiration, the relevant certification would generally be that the patent has expired or is not an obstacle to approval, rather than a conventional commercial Paragraph IV strategy.

What formulations are protected by the patent?

The patent is directed to a narrow particle-engineered formulation. The claim does not expressly require a particular excipient, dissolution profile, release profile, manufacturing process, or brand name.

Formulations likely within the literal claim scope

A formulation is a strong literal match if it contains:

7.5 mg of crystalline temazepam;
A measured surface area between 0.65 and 1.1 m²/g;
At least 95% of particles below 65 microns;
A conventional pharmaceutically acceptable carrier;
A hard gelatin capsule.

The same analysis applies to a 6, 6.5, 7, or 8 mg formulation under claim 1, assuming the other limitations are met.

Formulations likely outside the literal claim scope

A formulation may fall outside the literal claims if it uses:

More than 8 mg or less than 6 mg under claim 1;
A dose other than 7.5 mg under claim 2;
Surface area below 0.65 or above 1.1 m²/g;
A particle distribution in which fewer than 95% of particles are below 65 microns;
A noncrystalline or different solid-state form;
A tablet, oral solution, softgel, or other dosage form;
A delivery system without a hard gelatin capsule.

The doctrine of equivalents could theoretically reach a product outside a numerical boundary, but prosecution-history estoppel and the specificity of the numerical limitations would be important defenses. A court would also assess whether treating an out-of-range formulation as equivalent would improperly erase the claim's express numerical limits. [2]

What manufacturing and intellectual-property barriers does the patent create?

The patent's technical center is control of the active pharmaceutical ingredient rather than the capsule shell or a particular manufacturing sequence. A manufacturer would need to control:

Crystallization conditions;
Crystal form and solid-state identity;
Milling or micronization;
Surface area;
Particle-size distribution;
Blend uniformity;
Encapsulation accuracy;
Batch-to-batch analytical testing.

These requirements can create process-development costs even after patent expiration. They do not, however, constitute a continuing legal exclusion. The formulation may also be subject to ordinary FDA chemistry, manufacturing, and controls requirements, including specifications for particle size, polymorphism, assay, impurities, dissolution, and content uniformity.

The patent does not appear, from the claims provided, to cover a unique manufacturing process. Its claims are product-and-formulation claims. A manufacturer could potentially design around them by using a different solid-state form or particle profile, although regulatory equivalence and product-performance requirements would remain.

How does this patent compare with broader temazepam protection?

Protection category	Covered by Patent 5,211,954?	Commercial significance today
Temazepam molecule	No	Molecule is long off patent
General temazepam composition	No, unless all claim limits are met	No current exclusion from this patent
7.5 mg hard gelatin capsule	Yes, only with specified physical properties	Patent expired
6-to-8 mg hard gelatin capsule	Yes, only with specified physical properties	Patent expired
15 mg or 30 mg capsules	Not under the stated claims	No coverage from these claims
Tablet formulation	No	Outside claim format
Oral solution	No	Outside claim format
Manufacturing method	Not expressly claimed in the provided claims	Must be assessed from the full patent
Method of treatment	No	No method-of-use claim shown
Biosimilar pathway	Not applicable	Temazepam is a small molecule, not a biologic

Temazepam is a small-molecule benzodiazepine. Biosimilar litigation and biologic exclusivity concepts do not apply. Generic applicants use the ANDA pathway, not the biosimilar pathway under the Public Health Service Act. [5,6]

Which companies are challenging the patent?

No current challenge is commercially material because the patent expired in 2010. The public patent and FDA framework does not make an expired formulation patent an ongoing barrier to generic approval or launch.

Temazepam has been marketed by multiple manufacturers through generic approvals. Brand and generic competition has included products associated with Restoril and ANDA-approved temazepam capsules. The presence of multiple approved manufacturers is consistent with the absence of an active exclusion based on Patent 5,211,954. [4]

A complete historical litigation answer would require docket-level review of district-court complaints, ANDA litigation, settlements, and FDA Paragraph IV notices. The claims alone do not establish that litigation occurred.

What is the patent's commercial and revenue impact?

The patent's commercial value was concentrated in the 7.5 mg capsule segment and related low-dose formulations. It did not cover all Restoril strengths and did not cover temazepam as an active ingredient.

The economic impact therefore depended on:

Whether the 7.5 mg product was commercially significant;
Whether the branded product relied on the claimed particle profile;
Whether other patents or regulatory exclusivities protected the product;
Whether generic applicants could design around the particle limitations;
The timing of any generic approval relative to the patent expiry.

After May 18, 2010, this patent could not support a continuing premium, injunction, or delayed generic launch. Current revenue exposure from the patent is effectively zero as a matter of patent exclusion. Commercial exposure may still arise from controlled-substance regulation, manufacturing compliance, product quality, and market demand, but those are separate from the expired patent.

How strong is the patent estate for this temazepam formulation?

The issued claims were technically narrow but potentially useful before expiration because they combined several measurable product attributes:

Dose;
Crystallinity;
Surface area;
Particle-size distribution;
Capsule type;
Carrier requirement.

That combination could make a formulation difficult to design around while preserving the same product performance. The estate was weaker against a product that differed clearly in particle distribution, surface area, solid-state form, or dosage form.

Its present legal strength is nil because the ordinary patent term has ended. Any remaining risk would have to come from a separate unexpired patent, regulatory exclusivity, a patent-term correction, or an unrelated formulation or manufacturing patent. The claims supplied do not show any such separate right.

Key Takeaways

U.S. Patent 5,211,954 is a narrow formulation patent, not a composition-of-matter patent for temazepam.
Claim 1 covers 6-to-8 mg crystalline temazepam capsules with specified surface area and particle-size limits.
Claim 2 specifically covers the 7.5 mg embodiment with the same physical-property limitations.
"Consisting essentially of" permits ordinary excipients but may exclude additives that materially alter the claimed formulation characteristics.
The patent issued May 18, 1993, and its ordinary 17-year term expired May 18, 2010.
The patent does not create a current Paragraph IV, Orange Book, biosimilar, or generic-launch barrier.
The critical historical infringement issues would have been analytical measurement, particle-size methodology, surface-area testing, crystal form, and capsule composition.
Current commercial risk must be assessed against other patents, FDA records, controlled-substance requirements, and product-specific regulatory obligations.

FAQs About U.S. Patent 5,211,954 and Temazepam

Does Patent 5,211,954 cover 15 mg temazepam capsules?

No. The claims provided cover 6-to-8 mg under claim 1 and exactly 7.5 mg under claim 2. A 15 mg capsule is outside those dose limitations.

Does the patent cover micronized temazepam?

Only if the micronized crystalline temazepam also satisfies the claimed surface-area range and particle-size distribution. "Micronized" alone is not enough.

Can a generic manufacturer use a different excipient blend?

Yes, in principle. Different excipients would not automatically avoid the claims, because the claims require a pharmaceutically acceptable carrier and use "consisting essentially of." The relevant question is whether the additional ingredients materially affect the claimed formulation characteristics.

Is temazepam subject to biosimilar competition?

No. Temazepam is a small-molecule drug. Competition proceeds through generic-drug approval, usually under an ANDA, rather than through the biosimilar pathway.

Could the patent still block a generic launch after 2010?

Not as an ordinary enforceable patent right. A separate unexpired patent, regulatory exclusivity, or an unusual term-related record would have to create the barrier. Patent 5,211,954 itself expired under its ordinary term in 2010.

Sources

United States Patent and Trademark Office. (1993). U.S. Patent No. 5,211,954.
U.S. Supreme Court. (1997). Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U.S. 17.
United States Code. 35 U.S.C. § 154.
U.S. Food and Drug Administration. (2024). Approved Drug Products with Therapeutic Equivalence Evaluations, 44th ed.
United States Code. 21 U.S.C. § 355(j).
U.S. Food and Drug Administration. (2024). Generic Drug Facts and the ANDA Approval Process.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Belgium	1000318	⤷ Start Trial
Canada	1302886	⤷ Start Trial
Switzerland	673947	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,211,954

Summary for Patent: 5,211,954